Bloodstain Pattern Evidencw Flashcards
(75 cards)
What is bloodstain Pattern Analysis?
Feature-based pattern recognition that studies the shape, size, location and distribution of bloodstains.
What type of information is provided by bloodstain pattern analysis?
Provides information about the event(s) that created the bloodstains and patterns
What is meant by BPA being an applied science?
A science based upon severak other scientific disciplines.
List the other disciplines BPA is based on.
5
Biochemistry
Physics
Fluid mechanics
Trajectory analysis
Chemistry
In what types of investigations is BPA used?
5
Homicides
Non-homicide death investigations
Serious assaults
SAs
Serious industrial accidents
What information can BPA provide?
7
Impact location(s)
Minimum number of impacts
Object or mechanism used to create pattern
Position of person bleeding
Movement of people and objects during bloodshed
Movement of people and objects after bloodshed
Sequence of events
Describe the contributions Dr. Edouard Piotrowski made to BPA.
3
Recognized the dynamic nature of blood in flight asa result of blows
Conducted experiments striking live rabbits with various implements
Documented the resulting bloodstain patterns through hand drawings.
What was the significance of The Queen vs. Campbell 1872?
Dr. Moore Sr. and Dr. Foster describe bloodstains found on the suspect’s dress found on scene
What was the significance of R. vs. McPherson & Burke 1878?
Professor Ellis described bloodstain found on the suspect’s clothing.
Stated that the trousers had been washed after being bloodstained, based on chemical tests for blood.
When did Dr. Fred Carter develop software for blood drop simulation and area of origin calculations?
1989
Outline the process of becoming a bloodstain pattern analyst in Canada.
5
Understudy program ~2-3 years
Classroom study
Lab experiments
Scene attendance with mentor
Written and practical assessments
About how many bloodstain pattern analysts are there in Canada?
20-30
When was the International Association of Bloodstain Pattern Analysts formed?
1983
What was the purpose of the International Association of Bloodstain Pattern Analysts?
Professional org established to exchange ideas and standardize BPA practices.
How much blood is in the average adult?
~5 L
Describe the composition of blood.
55% plasma
45% erythrocytes
<1% leukocytes and platelets
What type of fluid is blood?
Non-Newtonian
What is viscosity?
Resistance to movement or flow
Compare the viscosities of blood and water.
Blood is approx. 3-5 times more viscous than water
Describe surface tension of blood.
Elastic like property of the surface of blood that tends to make it contract.
Describe what surface tension is.
A molecule in a liquid is attracted to surrounding molecules.
A surface molecule does not have molecules above, attraction is not balanced.
This creates a net force towards the inside of the liquid, pulling the surface molecule inward.
Describe what is meant by blood being a non-Newtonian fluid.
Blood viscosity decreases as shear force is applied.
Why is the non-Newtonian fluid property of blood important?
It allows blood to move through small blood vessels.
Give examples of other shear-thinning fluids.
Ketchup
Whipped cream
Motor oil